US4531398A - Calibration system for gas analyzers - Google Patents
Calibration system for gas analyzers Download PDFInfo
- Publication number
- US4531398A US4531398A US06/515,034 US51503483A US4531398A US 4531398 A US4531398 A US 4531398A US 51503483 A US51503483 A US 51503483A US 4531398 A US4531398 A US 4531398A
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- US
- United States
- Prior art keywords
- permeation
- tube
- chamber
- mixer
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0006—Calibrating gas analysers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Definitions
- the present invention relates to a calibration system for gas analyzers, particularly for apparatus measuring atmospheric pollution.
- measuring networks For studying atmospheric pollution (gaseous pollutants, fumes, particles), measuring networks are used, constituted by stations distributed over a given territory. In these stations, gas analyzers permanently measure the contents of the pollutants studied. In order to obtain reliable results of analysis, it is necessary periodically to calibrate the gas analyzers with the gaseous pollutants which are monitored. Furthermore, it is also necessary to ensure the physical intercalibration of the analyzing apparatus, i.e. to ensure that the pollutant and air standards and the sampled air are taken in the measuring station under the same conditions.
- Calibration systems are already known which use liquefied pollutant gases contained in permeation tubes generally made of "Teflon".
- One of the walls of this tube is generally scavenged by "zero air”, i.e. air containing no pollutant, or another gas such as nitrogen, at a constant rate of flow, the zero air or nitrogen passing around the permeation tube.
- the pressure of the liquid pollutant contained within the permeation tube is equal to the saturating vapour pressure, and because the partial pressure of the pollutant in the zero air or the nitrogen which passes about the permeation tube is zero, the existence of a pollutant pressure gradient on either side of the wall of the tube is created, such gradient causing the pollutant(s) to diffuse through the wall of the tube from the interior of the tube towards the exterior of the tube. This pressure gradient remaining constant, the rate of diffusion through the tube remains constant.
- this calibration system for gas analyzers particularly for apparatus for measuring atmospheric pollution detecting gaseous pollutant comprises a tight permeation chamber connected to a source of a gaseous pollutant or a plurality of chemically compatible gaseous pollutants such as SO 2 , NO, or CH 4 , a tube made of a material permeable to the pollutant gas extending across this chamber, one end of this tube being connected to a source of pure vector gas under pressure and its other end communicating with a mixer itself connected to a source of dilution zero air, and means for regulating the temperature to maintain a predetermined constant temperature inside the permeation chamber.
- a tight permeation chamber connected to a source of a gaseous pollutant or a plurality of chemically compatible gaseous pollutants such as SO 2 , NO, or CH 4
- a tube made of a material permeable to the pollutant gas extending across this chamber, one end of this tube being connected to a source of pure vector gas under pressure and its other end communicating with a mixer
- the gaseous permeation tube housed in the permeation chamber is preferably made of "Teflon", in the case of an aggressive gaseous pollutant, or silicon in the case of a less aggressive gaseous pollutant, such as SO 2 , NH 4 , or of any other polymer presenting advantageous characteristics for the permeation technique.
- the calibration system according to the invention offers various advantages over the known apparatus.
- the system can be emptied and refilled as desired with any gas compatible with the polymer used for the permeation tube, this allowing unlimited re-use.
- gaseous pollutants are used, the rate of permeation may be regulated as desired by adjusting the pressure of the gaseous pollutant and possibly the number of holes offered for diffusion, in the case of the permeation tube being fitted on a perforated steel tube.
- the apparatus according to the invention may also use a mixture of several compatible gaseous pollutants. All gases such as NO, CO, CH 4 , etc . . . can therefore be diffused, and not solely those which are liquefiable in the conventional permeation tubes such as SO 2 , NO 2 , H 2 S. As the gaseous pollutant is outside the permeation tube where diffusion takes place and as the gas entraining the pollutant licks (contacts and mixes with) the pollutant inside the tube, a symmetry of revolution for diffusion and consequently the total absence of unemployed volume detrimental to the constancy of the rate of diffusion are obtained.
- the permeation device may work with mixtures of chemically compatible gases. All these gases diffuse together and follow the same destiny. Consequently an abnormality on one of the constituents of the mixture will be found on the others and, inversely, correct operation on one of the gaseous ensures that the operation for the other gases must be correct. In this way the calibrator is very safe, as the system is "blind".
- the permeation temperature, the rate of flow of air and the filling pressure of the pollutant are monitored.
- the use of titration in gaseous phase of which the reaction is rapid and complete, due to the rapid and high concentration of O 3 and NO in the reaction chamber, further strengthens the interdependence of all the pollutants.
- the permeation temperature is preferably set at 64° C., this ensuring that, whatever the place of use, the variation between the ambient temperature and that of the permeation device will always be sufficient for the regulation of temperature (from a D.C. source at 12 V) to operate under good conditions. On the contrary, this is not the case of the known apparatus using liquid permeation tubes which cannot rise to such a temperature due to the excessively high pressures attained by the pollutants within the permeation tube.
- a further advantage of the system according to the invention is that it does not require a cylinder of NO, since this gas is obtained by permeation within the system and, in addition, the rate of flow of zero air or of nitrogen scavenging the tube does not need to be regulated: it must simply ensure that the partial pressure of the pollutant within the tube is zero for the rate of diffusion to remain constant.
- the nitrogen constituting the vector gas containing the pollutants represents less than 1% of the final rate of flow, the final concentration of the or each pollutant at the outlet of the system is therefore independent of the rate of flow of nitrogen.
- NO is obtained directly from a cylinder at 100 ppm (for example) nd consequently the rate of flow of this cylinder must be carried fully regulated so that the final concentration remains constant.
- the dilution gas must be a zero air not containing the pollutants produced by the system.
- a zero air in NO, NO 2 , SO 2 and O 3 is obtained by passing the air drawn in by a pump around an ozone generator: O 3 thus produced then completely oxidizes into NO 2 and then SO 2 , O 3 and NO which are possibly present in the ambient air are then fixed on active carbon, NO having been previously converted into NO 2 .
- Another advantage of the system according to the invention is that the life duration of a filling may attain several years and, furthermore, this system is always ready for operation since it remains operational during transport (being supplied from a 12 V battery of a vehicle) and since, with its internal batteries, it is self-sufficient for thirty hours.
- FIG. 1 is a circuit diagram of a calibration system for gas analyzers according to the invention, using a gaseous permeation tube.
- FIG. 2 is a detailed diagram of an embodiment of the calibration system according to the invention.
- FIG. 3 is a view in axial section of a gaseous permeation tee.
- FIG. 4 is a view in axial section, partly in elevation, of a gaseous permeation cell.
- the calibration system according to the invention, of which the principle is illustrated by the diagram of FIG. 1, comprises a tight permeation chamber 1 which is connected, by a stop valve 2, to a source 3 of at least one pollutant gas.
- This permeation chamber 1 has a permeation tube 4 made of a material permeable to the pollutant gas, such as silicon or other polymers, passing right through it.
- the pressure of the pollutant gas in the chamber 1 is indicated by a pressure gauge 5.
- One end of the permeation tube 4 is connected, via a valve 6 and a pipe coil 7, to a source 8 of a vector gas which may be "zero" air, i.e.
- the permeation tube 4 is connected to a mixer 9 in which a dilution zero air flow is also directly introduced through a valve 11.
- the permeation chamber 1 as well as the coil 7 are housed in an enclosure 12 of which the temperature is regulated so as to be maintained constant, for example equal to 64° C.
- the vector gas (“zero" air or nitrogen) flows through the permeation tube 4, at a rate of flow adjustable by the valve 6. Furthermore, the or each pollutant gas is introduced into the permeation chamber 1, all around the permeation tube 4, at an adjustable partial pressure controlled by means of the pressure gauge 5. Inside the permeation tube 4, the partial pressure of the pollutant gas is virtually zero. On both sides of the wall of the permeation tube 4, there is therefore a gradient of concentration. If this gradient is maintained constant, i.e. if the partial pressure of the pollutant gas in the chamber 1 is maintained constant around tube 4, the speed of diffusion, i.e. the quantity of pollutant which passes through the wall of the tube 4 per unit of time, is constant.
- the permeation chamber is constituted by a tee 13 shown in detail in FIG. 3.
- This tee comprises a body which is pierced right through with a bore 14 through which extends a permeation tube 15 made for example of "Teflon".
- the body of the tee 13 is provided at the two ends of the bore 14 with threaded unions 16, 17 on which are screwed respective nuts 18 and 19 through which the permeation tube 15 passes. These nuts ensure blockage of the tube 15 in the unions 16, 17 via respective conical rings 21, 22. This type of union is known under the name of "Swagelock".
- the outer diameter of the permeation tube 15 is smaller than the diameter of the bore 14 so as to define with the wall of the latter a chamber in which the gaseous pollutant is introduced.
- This pollutant is supplied through a pipe 23 which is fixed, by means of a nut 24, to a threaded union 25 surrounding a transverse conduit 26 opening out perpendicularly into bore 14 at the centre thereof.
- the permeation tube 15 is connected, at one of its ends, to a nitrogen cylinder 27 (FIG. 2), whilst its other end is connected to a three-way valve 28.
- This valve ensures communication with a reaction chamber 29 which is connected, via a pipe 31, to a sampling mixer 32.
- This mixer 32 is provided with a plurality of outlet connectors 33 adapted to be connected to the gas analyzers, as well as with a pipe 34 for the evacuation of excess of the mixture.
- the atmospheric air is drawn through a filter 35 which is connected to one end of the coil 7 housed, with the permeation tee 13, inside the heat-regulated enclosure.
- the coil 7 is in turn connected to a nitrogen generator 36 of which the interior communicates, via a pipe 37 on which is connected an active charcoal filter 38, with the suction orifice of a pump 39.
- Elements 41, 42, 43 introducing variable pressure drops are connected to the intake orifice of the pump 39 to make it possible to set three different rates of flow of this pump, namely 78 l/hr., 135 l/hr. and 335 l/hr. for example.
- the delivery orifice of pump 39 is connected on the one hand to the sampling mixer 32, through a pressure drop element 44, and on the other hand to a threeway valve 45, via another pressure drop element 46.
- the rate of flow Q of zero gas furnished by the pump 39 is divided into two, namely a relatively high rate of flow (for example 0.9 Q) directed directly towards the mixer 32 and on the other hand a lower rate of flow (for example 0.1 Q) directed towards the three-way valve 45.
- This low rate of flow may be directed by this valve, in a first position thereof, so that it passes, as vector gas, through a quartz tube 47 extending across the ozone generator 36 and communicating, at its opposite end, with the reaction chamber 29.
- the ozone generator creates ozone in a well known manner within quartz tube 47 by passing ultraviolet light through the quartz, which is permeable or transparent to such light, so that the light will interact with the oxygen in the tube provided from the ambient air to form ozone.
- the ozone generator 36 In a second position of the valve 45, the ozone generator 36 is shortcircuited and the flow of zero air is directed directly towards the reaction chamber 29.
- References 100 and 200 in FIG. 2 represent the first and second positions of the three-way valve 45, respectfully.
- the or each pollutant gas is contained in one large-volume cell 48 which is connected to the permeation tee 13 by pipe 23.
- This cell 48 of which the pressure is indicated by a pressure gauge 49, may contain, for example, SO 2 , NO, CH 4 , C 3 H 8 , etc . . . .
- the heat-regulated enclosure 12 is maintained at an appropriate temperature, of the order of 64° C.
- the temperature of the heat-regulated enclosure 12 is maintained constant by an electrical regulation circuit which may be supplied either from an A.C. source, in a station, or from a portable accumulator incorporated in the system.
- the vector gas furnished to the permeation chamber 13 is constituted by nitrogen contained in cylinder 27, the nitrogen being furnished at a very low rate of flow.
- This rate of flow does not need to be regulated since the speed of permeation does not depend on the rate of flow of the nitrogen or the zero air, provided that the partial pressure of the gaseous pollutant of the vector gas is zero and that the rate of flow of the vector gas is very low with respect to the final rate of flow obtained at mixer 32.
- the rate of flow of nitrogen in the permeation chamber 13 is less than one hundredth of the rate of flow of dilution gas furnished by the pump 39 to the mixer 32.
- the ambient air drawn in by pump 39 passes onto the ozone generator 36 in order to oxidize the NO of the ambient air into NO 2 : under these conditions, NO 2 and the excess of ozone are adsorbed on the active charcoal filter 38 as well as SO 2 or other pollutants adsorbable on active charcoal.
- the pump 39 thus draws in the zero air, whose rate of flow may be regulated by the pressure drop elements 41, 42, 43, this zero air not containing any pollutant such as NO, SO 2 , NO 3 , NO 2 .
- gas analyzers may be supplied at the same time, particularly ozone and nitrogen oxide analyzers, in order to verify correct functioning of the titration in gaseous phase.
- the three-way valve 45 makes it possible to use, or not, titration in gaseous phase.
- This cell comprises a hermetically closed cylindrical chamber 51 connected, by a stop valve 52, to a source of gaseous pollutant (sulfuretted hydrogen), the pressure in the chamber 51 being indicated by a pressure gauge 53.
- This cylindrical chamber 51 bears, on its two front faces, inlet and outlet unions 54 and 55 through which pass respective metal tubes 56, 57 which are blocked by means of nuts 58, 59.
- the two tubes 56, 57 extend coaxially inside the cylindrical chamber 51 and are welded, at their ends, to an intermediate tube 61 of smaller diameter, made of stainless steel.
- This tube is pierced, over a part of its length, by a certain number of holes 62. Furthermore, a permeation tube 63 is fitted on the perforated tube 61.
- the gaseous pollutant which is under pressure inside the cylindrical chamber 51 may diffuse through the permeation tube 63 which is made of silicon or another polymer, and may pass through the holes 62 in the stainless steel inner tube 61.
- the gaseous pollutant thus passes in the vector gas which traverses the permeation chamber 51 from left to right, through the tubes 56, 61, 57, the rate of permeation being a function of the gaseous pollutant as well as of the number of perforated holes in tube 61.
- the pressure of the gaseous pollutant in the chamber 51 or possibly the number of holes of the perforated tube 61 may be varied.
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Food Science & Technology (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Sampling And Sample Adjustment (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8213104A FR2531220A1 (fr) | 1982-07-27 | 1982-07-27 | Appareil d'etalonnage d'analyseurs de gaz |
FR8213104 | 1982-07-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4531398A true US4531398A (en) | 1985-07-30 |
Family
ID=9276360
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/515,034 Expired - Fee Related US4531398A (en) | 1982-07-27 | 1983-07-18 | Calibration system for gas analyzers |
Country Status (4)
Country | Link |
---|---|
US (1) | US4531398A (fr) |
EP (1) | EP0100281B1 (fr) |
DE (1) | DE3368126D1 (fr) |
FR (1) | FR2531220A1 (fr) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4630038A (en) * | 1984-05-01 | 1986-12-16 | Jordan Mark A | Vapor concentration control |
US5092218A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Selective detection of explosives vapors |
US5092220A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Nitric oxide detection with hydrogen and ozone |
US5207087A (en) * | 1991-04-17 | 1993-05-04 | Optex Biomedical, Inc. | Sensor calibrator and test apparatus |
US5213769A (en) * | 1991-10-30 | 1993-05-25 | Whitlock Walter H | Mixture forming method and apparatus |
US5329804A (en) * | 1992-10-16 | 1994-07-19 | Abbott Laboratories | Calibration system and method for calibrating a blood gas sensor |
US5597535A (en) * | 1994-02-25 | 1997-01-28 | Tekran Inc. | Apparatus for detecting mercury |
US5753832A (en) * | 1994-11-03 | 1998-05-19 | Thermedics Detection Inc. | Vapor and particle sampling |
US5986240A (en) * | 1998-01-06 | 1999-11-16 | Mg Industries | Method and apparatus for maintaining contents of a compressed gas cylinder at a desired temperature |
US6110257A (en) * | 1997-05-16 | 2000-08-29 | Advanced Technology Materials, Inc. | Low concentration gas delivery system utilizing sorbent-based gas storage and delivery system |
US20050000981A1 (en) * | 2003-07-02 | 2005-01-06 | Industrial Scientific Corporation | Apparatus and method for generating calibration gas |
WO2008017884A2 (fr) * | 2006-08-08 | 2008-02-14 | Owlstone Ltd | Générateur de vapeur |
CN102539311A (zh) * | 2012-01-13 | 2012-07-04 | 北京科技大学 | 一种微量腐蚀性气体环境试验箱 |
CN110441484A (zh) * | 2019-09-23 | 2019-11-12 | 深圳市无眼界科技有限公司 | 一种空气气态污染物的检测装置及检测系统 |
WO2021188985A2 (fr) | 2020-03-19 | 2021-09-23 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Système de perméation concentrique pour le transfert de matériau gazeux neutre |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
LU85955A1 (de) * | 1985-06-17 | 1986-06-25 | Euratom | Vorrichtung zur erzeugung eines definierten gas/staub-gemisches |
EP0456527A1 (fr) * | 1990-04-06 | 1991-11-13 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Appareil pour fabriquer du gaz |
Citations (15)
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AT253243B (de) * | 1964-08-29 | 1967-03-28 | Brown Boveri Krupp Reaktor | Vorrichtung zum Dosieren einer Gasmenge |
US3521865A (en) * | 1968-05-20 | 1970-07-28 | Du Pont | Generation of accurately known vapor concentrations by permeation |
US3533272A (en) * | 1968-06-03 | 1970-10-13 | Harald Dahms | Preparation of gas mixtures |
US3618911A (en) * | 1969-09-05 | 1971-11-09 | Marlabs Inc | Dynamic gas-mixing apparatus |
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US3776023A (en) * | 1971-12-22 | 1973-12-04 | Monitor Labs Inc | Calibration system for gas analyzers |
US3788545A (en) * | 1971-12-27 | 1974-01-29 | Monitor Labs Inc | Gas permeation tube and method for the filling thereof |
US3824836A (en) * | 1972-11-21 | 1974-07-23 | Combustion Equipment Ass | Gas permeator |
US3948604A (en) * | 1974-01-02 | 1976-04-06 | Borg-Warner Corporation | Alcoholic breath simulation system |
US4036915A (en) * | 1973-01-02 | 1977-07-19 | Meloy Laboratories, Inc. | Temperature-controlled apparatus for fluid permeation or the like |
US4164861A (en) * | 1978-02-17 | 1979-08-21 | Inficon Leybold-Heraeus Inc. | Leak standard generator |
US4209300A (en) * | 1978-09-25 | 1980-06-24 | The United States Of America As Represented By The Department Of Health, Education And Welfare | Hemoglobin-oxygen equilibrium curve analyzer |
SU748167A1 (ru) * | 1978-04-04 | 1980-07-15 | Предприятие П/Я Р-6900 | Генератор поверочных газовых смесей |
US4279142A (en) * | 1975-09-25 | 1981-07-21 | Westinghouse Electric Corp. | Technique for in situ calibration of a gas detector |
JPS57173740A (en) * | 1981-04-20 | 1982-10-26 | Kimoto Denshi Kogyo Kk | Referense gas producer for calibration of nitrogen oxide concentration measuring device |
-
1982
- 1982-07-27 FR FR8213104A patent/FR2531220A1/fr active Granted
-
1983
- 1983-07-18 US US06/515,034 patent/US4531398A/en not_active Expired - Fee Related
- 1983-07-25 EP EP83401522A patent/EP0100281B1/fr not_active Expired
- 1983-07-25 DE DE8383401522T patent/DE3368126D1/de not_active Expired
Patent Citations (15)
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AT253243B (de) * | 1964-08-29 | 1967-03-28 | Brown Boveri Krupp Reaktor | Vorrichtung zum Dosieren einer Gasmenge |
US3521865A (en) * | 1968-05-20 | 1970-07-28 | Du Pont | Generation of accurately known vapor concentrations by permeation |
US3533272A (en) * | 1968-06-03 | 1970-10-13 | Harald Dahms | Preparation of gas mixtures |
US3618911A (en) * | 1969-09-05 | 1971-11-09 | Marlabs Inc | Dynamic gas-mixing apparatus |
US3689038A (en) * | 1971-04-13 | 1972-09-05 | Marlabs Inc | Dynamic gas flow apparatus |
US3776023A (en) * | 1971-12-22 | 1973-12-04 | Monitor Labs Inc | Calibration system for gas analyzers |
US3788545A (en) * | 1971-12-27 | 1974-01-29 | Monitor Labs Inc | Gas permeation tube and method for the filling thereof |
US3824836A (en) * | 1972-11-21 | 1974-07-23 | Combustion Equipment Ass | Gas permeator |
US4036915A (en) * | 1973-01-02 | 1977-07-19 | Meloy Laboratories, Inc. | Temperature-controlled apparatus for fluid permeation or the like |
US3948604A (en) * | 1974-01-02 | 1976-04-06 | Borg-Warner Corporation | Alcoholic breath simulation system |
US4279142A (en) * | 1975-09-25 | 1981-07-21 | Westinghouse Electric Corp. | Technique for in situ calibration of a gas detector |
US4164861A (en) * | 1978-02-17 | 1979-08-21 | Inficon Leybold-Heraeus Inc. | Leak standard generator |
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US4209300A (en) * | 1978-09-25 | 1980-06-24 | The United States Of America As Represented By The Department Of Health, Education And Welfare | Hemoglobin-oxygen equilibrium curve analyzer |
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Non-Patent Citations (8)
Title |
---|
"Advances in Instrumentation", vol. 31, No. 3 (1976), Design Criteria for a Portable Gas Phase Titration Calibration System, p. 710, lines 1-6 and FIGS. 3 and 4, Jerry Clemons et al., (6 sheets). |
"Generator for Producing Trace Vapor Concentrations of 2,4,6-Trinitrotoluene, 2,4-Dinitrotoluene, and Ethylene Glycol Dinitrate for Calibrating Explosives Vapor Detectors"; Analytical Chemistry, vol. 48, No. 11, Sep. 1976, pp. 1632-1637, Peter A. Pella. |
Advances in Instrumentation , vol. 31, No. 3 (1976), Design Criteria for a Portable Gas Phase Titration Calibration System, p. 710, lines 1 6 and FIGS. 3 and 4, Jerry Clemons et al., (6 sheets). * |
Generator for Producing Trace Vapor Concentrations of 2,4,6 Trinitrotoluene, 2,4 Dinitrotoluene, and Ethylene Glycol Dinitrate for Calibrating Explosives Vapor Detectors ; Analytical Chemistry, vol. 48, No. 11, Sep. 1976, pp. 1632 1637, Peter A. Pella. * |
Hughes et al., article from "Advances in Instrumentation", vol. 29, No. 3 (1974), entitled Development of Standard Reference Materials for Air Quality Measurement, p. 704, lines 1-13 (13 sheets). |
Hughes et al., article from Advances in Instrumentation , vol. 29, No. 3 (1974), entitled Development of Standard Reference Materials for Air Quality Measurement, p. 704, lines 1 13 (13 sheets). * |
Scaringelli et al., excerpt from "Analytical Chemistry", vol. 42, No. 8, Jul. 1970, pp. 871-876. |
Scaringelli et al., excerpt from Analytical Chemistry , vol. 42, No. 8, Jul. 1970, pp. 871 876. * |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4630038A (en) * | 1984-05-01 | 1986-12-16 | Jordan Mark A | Vapor concentration control |
US5092218A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Selective detection of explosives vapors |
US5092155A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | High speed detection of vapors of specific compounds |
US5092220A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Nitric oxide detection with hydrogen and ozone |
US5092217A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Method of calibrating a vapor detector |
US5092157A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Vapor collector/desorber with metallic ribbon |
US5098451A (en) * | 1987-07-08 | 1992-03-24 | Thermedics Inc. | Vapor concentrator |
US5099743A (en) * | 1987-07-08 | 1992-03-31 | Thermedics Inc. | Selective detection with high speed gas chromatography |
US5123274A (en) * | 1987-07-08 | 1992-06-23 | Thermedics Inc. | Hand-held sample gun for vapor collection |
US5207087A (en) * | 1991-04-17 | 1993-05-04 | Optex Biomedical, Inc. | Sensor calibrator and test apparatus |
US5213769A (en) * | 1991-10-30 | 1993-05-25 | Whitlock Walter H | Mixture forming method and apparatus |
AU640878B2 (en) * | 1991-10-30 | 1993-09-02 | Boc Group, Inc., The | Mixture forming method and apparatus |
US5329804A (en) * | 1992-10-16 | 1994-07-19 | Abbott Laboratories | Calibration system and method for calibrating a blood gas sensor |
US5660795A (en) * | 1994-02-25 | 1997-08-26 | Tekran Inc. | Cartridge for collection of a sample by adsorption onto a solid surface |
US5597535A (en) * | 1994-02-25 | 1997-01-28 | Tekran Inc. | Apparatus for detecting mercury |
US5753832A (en) * | 1994-11-03 | 1998-05-19 | Thermedics Detection Inc. | Vapor and particle sampling |
US5760314A (en) * | 1994-11-03 | 1998-06-02 | Thermedics Detection Inc. | Vapor and particle sampling |
US6110257A (en) * | 1997-05-16 | 2000-08-29 | Advanced Technology Materials, Inc. | Low concentration gas delivery system utilizing sorbent-based gas storage and delivery system |
US5986240A (en) * | 1998-01-06 | 1999-11-16 | Mg Industries | Method and apparatus for maintaining contents of a compressed gas cylinder at a desired temperature |
US6997347B2 (en) * | 2003-07-02 | 2006-02-14 | Industrial Scientific Corporation | Apparatus and method for generating calibration gas |
US20050000981A1 (en) * | 2003-07-02 | 2005-01-06 | Industrial Scientific Corporation | Apparatus and method for generating calibration gas |
WO2008017884A2 (fr) * | 2006-08-08 | 2008-02-14 | Owlstone Ltd | Générateur de vapeur |
WO2008017884A3 (fr) * | 2006-08-08 | 2008-05-02 | Owlstone Ltd | Générateur de vapeur |
CN102539311A (zh) * | 2012-01-13 | 2012-07-04 | 北京科技大学 | 一种微量腐蚀性气体环境试验箱 |
CN102539311B (zh) * | 2012-01-13 | 2013-07-03 | 北京科技大学 | 一种微量腐蚀性气体环境试验箱 |
CN110441484A (zh) * | 2019-09-23 | 2019-11-12 | 深圳市无眼界科技有限公司 | 一种空气气态污染物的检测装置及检测系统 |
WO2021188985A2 (fr) | 2020-03-19 | 2021-09-23 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Système de perméation concentrique pour le transfert de matériau gazeux neutre |
US11476105B2 (en) * | 2020-03-19 | 2022-10-18 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Concentric permeation system for transfer of neutral gaseous material |
EP4121751A4 (fr) * | 2020-03-19 | 2024-04-10 | The Government of the United States of America, as represented by the Secretary of the Navy | Système de perméation concentrique pour le transfert de matériau gazeux neutre |
Also Published As
Publication number | Publication date |
---|---|
FR2531220B1 (fr) | 1985-05-17 |
FR2531220A1 (fr) | 1984-02-03 |
EP0100281A2 (fr) | 1984-02-08 |
DE3368126D1 (en) | 1987-01-15 |
EP0100281A3 (en) | 1984-04-04 |
EP0100281B1 (fr) | 1986-12-03 |
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